Cod sursa(job #2485477)

Utilizator filiptudose2007Tudose Filip filiptudose2007 Data 1 noiembrie 2019 17:31:38
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.16 kb
#include <bits/stdc++.h>
using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");
queue <int> Q;
vector <pair<int,int>> G[50005];
int n,m,x,y,cost,i,d[50005],nr[50005];
bool sel[50005];
bool bellmanford(){
    for(int i=1; i<=n; ++i)sel[i]=false,d[i]=INT_MAX;
    sel[1]=true;
    Q.push(1);
    d[1]=0;
    bool done=false;
    while(!Q.empty() && !done)
    {
        x=Q.front();
        Q.pop();
        sel[x]=false;
        for(auto it:G[x])
        {
            if(nr[it.second]>n)done=true;
            else if(d[x]+it.first<d[it.second])
            {
                d[it.second]=d[x]+it.first;
                if(!sel[it.second])
                {
                    Q.push(it.second);
                    sel[it.second]=true;
                }
                nr[it.second]=nr[x]+1;
                if(nr[it.second]>n)done=true;
            }
        }
    }
    return done;
}
int main()
{
    f>>n>>m;
    for(i=1; i<=m; ++i)
    {
        f>>x>>y>>cost;
        G[x].push_back({cost,y});
    }
    if(bellmanford())g<<"Ciclu negativ!\n";
    else for(i=2; i<=n; ++i)g<<d[i]<<' ';
    return 0;
}